scripts: sphinx-pre-install: Convert script to Python

Port scripts/sphinx-pre-install to Python. That allows
a better maintainance of the file.

Signed-off-by: Mauro Carvalho Chehab <[email protected]>
Signed-off-by: Jonathan Corbet <[email protected]>
Link: https://lore.kernel.org/r/8d236079545aff796900bde4cdaaf79411d04074.1754992972.git.mchehab+huawei@kernel.org

Author: mchehab